The impeller is made of a [Polypropylene (PP)] material that has a magnet inside.
Polypropylene (PP) is one of the most commonly used thermoplastics in the world. Polypropylene uses range from plastic packaging, plastic parts for machinery and equipment, and even fibers and textiles. PP material, also known as polypropylene, is a semi-crystalline thermoplastic that's a member of the polyolefin group of materials. It's made by catalytically polymerizing propylene and is the second most widely used plastic in the world, after polyethylene (PET).
The PP part of the impeller is coated with food-grade, BPA-free high-end TPE.
Thermoplastic elastomer (TPE) is a rubber-like material that's flexible and can be processed like plastic. It's a combination of polymers with both thermoplastic and elastomeric properties. TPEs are also known as thermoplastic rubber. They are safe enough to be used to make things like sippy cups and healthcare products like medical tubing.